Sheet separator

ABSTRACT

Apparatus for removing sheets one by one from a stack includes a transfer belt which engages one surface of a sheet on one end of a stack to remove it from the stack, and a convex surface stripper means disposed on the opposite side of the end sheet, the transfer belt looping about the convex surface for an angle which is greater than approximately 25* and pressing a sheet against it while it is being removed, so that the convex surface retards removal of adjacent sheets and separates the end sheet from the stack.

United States Patent Inventors Karl Rehm;

Hermann Schwarz. both of Constance, Germany Appl. No. 819,712 Filed Apr.28, 1969 Patented Aug. 3, 1971 Assignee LicentiaPatent-Verwaltungs-G.m.b.1i.

Frankfurt/am Main. Germany Priority Mar. 24, 1969 Germany P 19 14 839.11

SHEET SEPARATOR 2 Claims, 5 Drawing Figs.

11.8. CI. 271/35 Int. Cl. B6511 3/04 Field oiSearch 271/35, 37, 38, 36

[56} References Cited UNiTED STATES PATENTS 1,011,820 12/1911 Labombarde271/35 2,273,288 2/1942 Rouan 271/35 3,239,213 3/1966 Griswold 271/353,288,461 11/1966 Smith 271/35 Primary Examiner-Joseph WegbreitAttorney-Spencer and Kaye ABSTRACT: Apparatus for removing; sheets oneby one from a stack inc1udes a transfer belt which engages one surfaceof a sheet on one end of a stack to remove it from the stack, and aconvex surface stripper means disposed on the opposite side of the endsheet, the transfer belt looping about the convex surface for an anglewhich is greater than approximately 25 and pressing a sheet against itwhile it is being removed, so that the convex surface retards removal ofadjacent sheets and separates the end sheet from the stack.

Patented Aug. 3, 1971 3,596,901

2 Sheets-Sheet 1 omvs CONTROL 1 CIRCUIT 5 E mvmons F|G.Z. KorlRehmaHermann Schworz MM! Ayg ATTORNEYS Patented Aug. 3, 1911 3,5963% 2Sheets-Sheet 2 .mvsmoxs Karl Rehm 8 Hermann Schwurz BY W ATTORNEYSSIHIIEIET SIEIPAIRATOIR BACKGROUND OF THE INVENTION 1. Field oftheInvention This invention relates to a device for individually removingsheets, one by one, from a stack, and more particularly to such a devicein which a moving transfer belt engages one surface of a sheet on theend of a stack to remove it therefrom, while the convexly curvedstripper engages the opposite surface of sheets in the stack to retardremoval of adjacent sheets and thus separate the end sheet from theadjacent sheets.

2. Description of the Prior Art Such a device is described in U.S. Pat.No. 1,214,474. The stripper of this device is a roller provided with afriction coating. A portion of the roller projects through a slot in aguide plate, and the roller is driven slowly in a direction opposite tothe direction in which the transfer belt moves. The frontal drive rollerfor the transfer belt is positioned opposite the stripping roller. Theoperating range within which the transfer belt and the stripping rollercan cooperate with each other to separate the end sheet from theadjacent sheets in the stack is relatively short. In this deviceseparation of the end sheet from the stack may fail to occurparticularly if the sheets are of uneven configuration or are deformed,as for example by being crumpled, limp, or torn. It is also possiblethat a number of sheets may become wedged together at a discharge pointso that manual removal of the wedged sheets is necessary beforeoperation ofthe apparatus can be resumed.

Such malfunctions are particularly undesirable if the apparatus is usedto separate individual pieces of paper currency in an automaticmoney-dispensing machine. Individual bills which have been in use fordiffering periods of time have very different paper properties,particularly with respect to coefficient of friction. Further variationsbetween bills occur because some bills may have become damaged.

SUMMARY OF THE INVENTION It is an object of the present invention toprovide a device of the above-described type, in which individual sheetsare reliably separated from the stack, which can be operated withoutattention for long periods of time, and in which malfunctions, if theyoccur at all, are automatically remedied.

Briefly stated, these and other objects of the invention are achieved inthat a stripping surface having a convex curvature is provided at thedischarge point of the stack and that the drive roller pulling thetransfer belt is so disposed adjacent said discharge point that thetransfer belt is looping about said stripping surface.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a schematic side view of oneembodiment of the present invention.

FIG. 2 is an enlarged view ofa portion of FIG. 1 illustrating aparticular operating situation.

FIG. 3 is a section along the line III-III of FIGURE ll.

FIG. 4 is a section along the line lV--IV ofFIGURE 1.

FIG. 5 is a schematic side view of another embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGURE 1, astack 31 of bills 1 is vertically arranged with the underside of thelowermost bill 32 resting upon a portion of the outer surface 3d of theforward reach ofa transfer belt 2. At the lowermost corner of the stackthere is disposed a rigid and nonrotatable cylindrical disc 3 whoseouter surface 3 is formed so as to have a higher coefficient of frictionthan that between adjacent sheets ofa stack.

Below the stack there is a support roller 4 which rotates about a fixedaxis to support the rear portion of the forward reach of transfer belt 2and the stack and a tension roller 5 which is mounted for longitudinalmovement in a support 6. The end of transfer belt 2 is looped about thetension roller 5. A weight 8 acts on tension roller 5 via a cable 7which is entrained about a guide roller 7 and pulls the belt 2 so as tomaintain it under constant tension. The other end, i.e. the front end ofthe forward reach of transfer belt 2 is looped about a drive roller 9.The coefficient of friction between the surface of transfer belt 2 andthe sheets is higher than that between said surface 3 and the sheets.

Drive roller 9 is so positioned relative to the stripper disc 3 and theguide roller 4 of the transfer belt 2 that the transfer belt is incontact with the stripper surface through an angle of approximately 60.

Referring to FIG. 3, it will be seen that drive roller 9 is fixed on adrive shaft 10 which is pivoted on support structure 45. Two freelyrotatable guide rollers 17 are rotatably mounted on the shaft 10 on eachside of the drive roller 9. A conveying belt 18 is entrained about eachof the guide rollers 17, and the belts together serve as a delivery beltfor sheets received from the transfer belt 2.

Referring now to FIG. 4, the same shows further details of the stripperdisc 3 and associated structure. Disc 3 is rigidly mounted on a shaft 19which is rigidly secured to support structure 40. A friction surface 3'is formed on the circumference of disc 3. Freely rotatable guide rollers20 are rotatably mounted on shaft 19 on each side of the disc 3. Guiderollers 20 have a lesser diameter than the disc 3. A delivery belt 21 isentrained about each of the guide rollers 20 and thereafter entrained sothat its outer surface 4 0 is in contact with the outer surface 42 ofdelivery belt 1% as the belts pass along about guide rollers 17. Thelower run 43 of the delivery belt 21 moves in contact with the upper runll of belt 118 so that a sheet, once delivered between belts 18 and 21by the transfer belt 2, is thereafter carried along to a furtherdestination. Delivery belts 18 and .21 are driven via appropriatelyarranged drive rollers 23 and 2A, which are illustrated in connectionwith the FIG. 5 embodiment and are independent of the drive of the driveroller 9 of the transfer belt 2.

A photoelectric barrier 25/25 is arranged adjacent the beginning of thecooperating runs of the delivery belts 18 and 21 so that it responds tothe passage of the front edge of a bill I pulled out of the stack by atransfer belt 2 through the barrier. An appropriate control signal isthen supplied through a drive control circuit Ml which then stops thedrive roller 9 of the transfer belt until the next call for a bill. Thedelivery conveyor belts 18 and 21, however, continue their movement tocarry the bill to its further destination, after which they may bestopped, although this is not relevant to the invention disclosed inthis application.

A plate 26 having a lesser coefficient of friction than the frictionsurface 3 is vertically arranged and is tangential to disc 3 on the sidefacing the stack. It provides a guide for the front edge of the stack ofbills 1.

Referring now to FIG. 5, a different embodiment of the apparatus formaintaining tension on the transfer belt 2 is shown. The apparatus isgenerally similar to that of FIG. 1 and corresponding parts havecorresponding reference numerals. As in that embodiment, the driveroller 9 and the support roller 4 of the transfer belt 2 are mounted forrotation about fixed axes. However, roller 5', unlike the tension roller5 of the FIG. ll embodiment is not movably mounted, but also rotatesabout a fixed axis and serves as an additional support roller for thetransfer belt 2. The loose reach 41-6 of the transfer belt 2 whichextends along its lower run is biased downwardly by a tension ing arm 13having a sliding guide 13' fastened thereto. Arm 13 is fixed to a disc12 which is rotatable around an axis Ill, and is biased into thetensioning position by a spring 16 which is secured to the disc 12 at12' and to fixed support structure 15. The arrangement of these elementsis such that, as is also true in the embodiment illustrated in FIG. 1,the belt tension is substantially independent of the position of thetransfer belt.

In an experimental type of a device substantially similar to thatillustrated in FIG. the stripper disc 3 was 95 mm. in diameter, theroller 9 56 mm. in diameter, the rollers 4 and 5 were 40 mm. indiameter. The rollers were each made of nylon plastic, roller 9 having acoating of natural rubber. Transfer belt 2 was l5 mm. in width and 580mm. long.

About disc 3 a coating of a synthetic known under the trade nameVulcollan" was formed which had a Shore hardness of 80. Vulcollan" is anelastomeric polyurethane. The surface which were finished by grindinghad a coefficient of friction of 0,5...0,6 to paper of the kindinvolved.

Transfer belt 2 were made of fabric coated with synthetic rubber andsold by the VIS-Kunststoffwerk Offenburg under the designation modelnumber C 10 in one version and B 08 in another version. A coefficient offriction of 0,7... 0,9 to paper were measured. The loose reach 46 oftransfer belt 2 was held under a tension of about 180 p (Pond). Allother belts were made from pure rubber.

Under the conditions indicated above an angle of enclosure at disc 3 ofabout 60 was found advantageous.

By varying the particular parameters concerned it has been found thatwith angles of enclosure smaller than about all other parametersoptimally choosen, the specific functional properties of a deviceaccording to the invention were not obtainable any more.

OPERATION OF THE PREFERRED EMBODIMENTS When it is desired to deliver abill I from the stack 31, the drive control means 44 is selectivelyoperated. Drive roller 9 is rotated and transfer belt 2 then pulls thelowermost bill 32 out of the stack and carries it into the regionbetween the delivery conveying belts 18 and 21. These belts then engagethe bill therebetween and pull it for delivery to a further point. Assoon as the front edge of the bill reaches the light barrier 25/25, asignal is supplied to the drive control means 44 and drive roller 9 ofthe transfer belt 2 is stopped. The delivery belts l8 and 21 continue tomove to completely pull the bill out of the separator device and tobring it to its further destination. Thereafter, they are alsoautomatically stopped.

Due to the fact that the transfer belt 2 encloses a stripping surface 3,an automatic adaptation to the varying frictional forces is realizedwhich result from the different paper consistencies of different bills.

With papers which are difficult to separate, for example, the enclosureresults in an increased belt tension in the pulling reach. As a resultof this, the bills are pressed closer to the transfer belt and into thestripping surface. Both the forward pushing force exerted by thetransfer belt 2 on the lowermost bill 32 and the retarding force exertedby the stripper surface 3 on the upper surface of the uppermost bill isincreased. The absolute value of the differential force on these billsincreases until finally the frictional force between the bills ismarkedly exceeded and separation is accomplished.

FIG. 2 shows a situation in which a number of bills I have advancedbetween a portion of the stripping surface 3 and the belt 2. Since thebelt tension in the loose reach is maintained constant, the play offorces is not interfered with during the removing process and isindependent of the fact whether or not the transfer belt is deflected toa greater or lesser degree.

If in a situation like that of FIG. 2 two or more bills are delivered tothe output of the device, this can be tolerated since the device may befollowed by a doubles detector not shown and a reject switch controlledby the same. It is essential however that under no circumstances wedgingof bills at the discharge point occurs and that malfunctions areautomatically remedied.

It will be understood that the above description of the presentinvention is susceptible to various modifications, changes andadaptations.

We claim:

1. In apparatus for separating sheets from a stack, which apparatusincludes rotatably mounted transfer belt means having a forward reachfor removing individual sheets from the stack, delivery means forreceiving each sheet removed from the stack by said belt means and fordelivering the sheets to a receiving point, means defining a convexstripping surface adjacent the outlet end of said apparatus, supportroller means supporting the rear portion of said forward reach, anddrive roller means supporting the front end of the forward reach of saidtransfer belt means for moving said belt means in a direction to conveysheets from the stack to said delivery means, said belt means having aloose return reach arranged to move in the opposite direction, saiddrive roller means being positioned for causing said forward reach to beurged against and conform to the shape of, said stripping surface alonga portion of its length which subtends an angle of more than about 25,the improvement wherein said portion of the length of said forward reachwhich conforms to the shape of said stripping surface is spaced from theparts of said forward reach which bear against said support roller meansand said drive roller means, said forward reach of said transfer beltmeans constitutes the sole sheet contacting surface opposite saidstripping surface in the vicinity of said stripping surface during allseparation operations, and the region at the opposite side of saidforward reach portion from said stripping surface is free of allobstructions, whereby the entirety of said forward reach portion may bedeflected away from said stripping surface by a distance equal to atleast several thicknesses of the sheets to be separated, and saidapparatus further comprises tension means connected to said belt meansfor maintaining its said return reach under a constant tension forcewhich is independent of changes in the belt configuration.

2. The combination defined in claim 1 wherein: said delivery meansincludes delivery belt means and drive means for driving said deliverybelt means, and said apparatus further comprises: means for sensing thedelivery of a sheet from the transfer belt to the delivery belt means,means responsive to said sensing means for stopping said drive roller ofthe transfer belt means while said drive means of the delivery beltmeans continues to operate, and means for starting the drive roller ofsaid transfer belt means when the delivery ofa new sheet is desired.

1. In apparatus for separating sheets from a stack, which apparatusincludes rotatably mounted transfer belt means having a forward reachfor removing individual sheets from the stack, delivery means forreceiving each sheet removed from the stack by said belt means and fordelivering the sheets to a receiving point, means defining a convexstripping surface adjacent the outlet end of said apparatus, supportroller means supporting the rear portion of said forward reach, anddrive roller means supporting the front end of the forward reach of saidtransfer belt means for moving said belt means in a direction to conveysheets from the stack to said delivery means, said belt means having aloose return reach arranged to move in the opposite direction, saiddrive roller means being positioned for causing said forward reach to beurged against and conform to the shape of, said stripping surface alonga portion of its length which subtends an angle of more than about 25*,the improvement wherein said portion of the length of said forward reachwhich conforms to the shape of said stripping surface is spaced from theparts of said forward reach which bear against said support roller meansand said drive roller means, said forward reach of said transfer beltmeans constitutes the sole sheet contacting surface opposite saidstripping surface in the vicinity of said stripping surface during allseparation operations, and the region at the opposite side of saidforward reach portion from said stripping surface is free of allobstructions, whereby the entirety of said forward reach portion may bedeflected away from said stripping surface by a distance equal to atleast several thicknesses of the sheets to be separated, and saidapparatus further comprises tension means connected to said belt meansfor maintaining its said return reach under a constant tension forcewhich is independent of changes in the belt configuration.
 2. Thecombination defined in claim 1 wherein: said delivery means includesdelivery belt means and drive means for driving said delivery beltmeans, and said apparatus further comprises: means for sensing thedelivery of a sheet from the transfer belt to the delivery belt means,means responsive to said sensing means for stopping said drive roller ofthe transfer belt means while said drive means of the delivery beltmeans continues to operate, and means for starting the drive roller ofsaid transfer belt means when the delivery of a new sheet is desired.